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authorMatthew Leach <matthew.leach@arm.com>2013-10-11 14:52:18 +0100
committerCatalin Marinas <catalin.marinas@arm.com>2013-10-25 15:59:42 +0100
commit710be9ac4ea0d2e02a2c4aa625795e65bf3db5b1 (patch)
tree8dce60344b354cfab9e78b62e223c413f7e6bae4 /arch/arm64
parentarm64: big-endian: set correct endianess on kernel entry (diff)
downloadlinux-dev-710be9ac4ea0d2e02a2c4aa625795e65bf3db5b1.tar.xz
linux-dev-710be9ac4ea0d2e02a2c4aa625795e65bf3db5b1.zip
arm64: big-endian: write CPU holding pen address as LE
Currently when CPUs are brought online via a spin-table, the address they should jump to is written to the cpu-release-addr in the kernel's native endianness. As the kernel may switch endianness, secondaries might read the value byte-reversed from what was intended, and they would jump to the wrong address. As the only current arm64 spin-table implementations are little-endian, stricten up the arm64 spin-table definition such that the value written to cpu-release-addr is _always_ little-endian regardless of the endianness of any CPU. If a spinning CPU is operating big-endian, it must byte-reverse the value before jumping to handle this. Signed-off-by: Matthew Leach <matthew.leach@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64')
-rw-r--r--arch/arm64/kernel/smp_spin_table.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/arch/arm64/kernel/smp_spin_table.c b/arch/arm64/kernel/smp_spin_table.c
index 27f08367a6e7..44c22805d2e2 100644
--- a/arch/arm64/kernel/smp_spin_table.c
+++ b/arch/arm64/kernel/smp_spin_table.c
@@ -72,7 +72,16 @@ static int smp_spin_table_cpu_prepare(unsigned int cpu)
return -ENODEV;
release_addr = __va(cpu_release_addr[cpu]);
- release_addr[0] = (void *)__pa(secondary_holding_pen);
+
+ /*
+ * We write the release address as LE regardless of the native
+ * endianess of the kernel. Therefore, any boot-loaders that
+ * read this address need to convert this address to the
+ * boot-loader's endianess before jumping. This is mandated by
+ * the boot protocol.
+ */
+ release_addr[0] = (void *) cpu_to_le64(__pa(secondary_holding_pen));
+
__flush_dcache_area(release_addr, sizeof(release_addr[0]));
/*